1. Field of the Invention
The present invention relates to an insertion apparatus including an insertion section inserted into a lumen inside, a pipe inside, or the like.
2. Description of the Related Art
In recent years, in a medical field, an industrial field, and the like, an electronic endoscope (hereinafter referred to as endoscope) incorporating an image pickup unit including solid-state image pickup device such as a CCD as an observation optical system at a distal end portion of an elongated insertion section has been used.
In some endoscopes, at a distal end portion of the endoscope, besides an observation unit, an illumination optical unit configuring an illumination optical system, a channel unit configuring a treatment instrument channel, a nozzle unit for air/water feeding, and the like are provided.
In an endoscope in which a bending section is provided in an elongated flexible insertion section, when observation, inspection, and the like are performed, the insertion section is inserted into a lumen of a living organism or into an engine, a pipe, or the like. In an endoscope in which a channel tube is provided along a longitudinal axis in an elongated insertion section, various kinds of medical treatment and the like can be performed by a treatment instrument led into a body via the channel tube and repairing and the like can be performed by a tool led into the pipe via the channel tube.
For example, Japanese Patent Application Laid-Open Publication No. H5-154101 discloses a slip-off preventing screw for fixing a channel distal end member to a distal end constituent member, a slip-off preventing screw for fixing a lens frame cover to the distal end constituent member, and a slip-off preventing screw for detachably attaching a unit main body of a lamp unit to the distal end constituent member.
Japanese Patent Application Laid-Open Publication No. H8-136829 discloses a screw for image pickup unit fixing for fixing a lens frame to a distal end constituent member, a pointed tip screw for fixing a nozzle to the distal end constituent member, and a screw for fixing a light guide to the distal end constituent member.
The endoscope described in the two Japanese publications above has a structure in which distal end side portions of endoscope internal components are fixed to the distal end constituent member by the screws. In order to realize a reduction in a diameter of the insertion section and firm fixing of the endoscope internal components to the distal end constituent member, the distal end constituent member is configured by a metal member and the number of threads is set to a minimum.